Let-off for looms



April 10, 1956 A. J. TOSCHES LET-OFF FOR LOOMS Filed June 27, 1952 2 Sheets-Sheet l INVENTOR. ANTHONY J. ToscHris A TTORNE Y April 10, 1956 J TQSCHES 2,741,272

LET-OFF FOR LOOMS Filed June 27, 1952 2 Sheets-Sheet 2 55 37 56 58 40 f 5 -fffj 4 I ANTHONY i 25 55 A TTORNE Y United States atent LET-OFFFOR LooMs Anthony J. Tosches, Milford, Mass., assignor to Braper Corporation, Hopedale, Mass., a corporation of Maine Application June27, 1952, Serial No. 295,908

4 Claims. (Cl. 139-110) advancing of the gearing interconnected to the beam and so to devise that advancing means that it shall function to advance the beam through extremely small and relatively uniform increments of movement.

.It is a more specific object of the invention to devise advancing means for such let-off motions which shall not depend upon a pawl motion of relatively great angular extent as has heretofore beenrequired, but will provide a practically continuous movement of the-parts throughout a very small angular extent, and therefore make .unnecessary greater periodic movement interspersed with relatively long periods of rest of the Warp mechanism. as has heretofore frequently been required.

It is a further more specific object of the invention to devise advancing means of the type described which shall be practically totally enclosed and which shall involve mainly mechanical elements of rotary type which are adapted to operate silently and which involve very little wearing of parts thus obviatingfrequent replacementand servicing.

It is a further object of the inventiontodevisean. advancing means in which the let-oif function shall berelatively continuous in that, as required, each pick Woven shall be accompanied by a corresponding and precise advance of the warp threads so that tensionmay be con trolled within very close limits.

It is a further object ofthe invention to devise a warp beam advancing means which shall function positively although the elements involved are smooth surfaced and their operation does not depend upon the interengagement of teeth of any type, and which is adapted to function positively although by simple mechanical .means,"the drive may be disengaged thereby to rotate the warp beam by hand in either direction as may be required.

Further objects of the invention will be apparent from the following more detailed description.

According to previous practice, warp beams mounted on weaving looms have been rotated to release the Warp threads being drawn under tension whenever tension has exceeded'a predetermined amount. The control for such function has been governed by certain movable elements affected by the tension of the threads themselves which in' turnicontrol the amplitude of movement of other periodically and continuously actuated parts functioning to impart a motion to a beam driving gear train through a ratchet wheel and .pawl or pawls. One form of such mechanism commonly employed includes agear train, in which are to be found a worm wheel and worm fordriving the same, said worm'being mounted on a shaft on which a brake drum is also fixed. Brake shoes areapplied to the drum in a known manner so that normally the said brake prevents rotation of the worm even though the warp threads are drawn under considerable tension except as the let-ofiorthe advancing-means ,comprisinga ratchet wheel and ratcheting pawl-mechanism function to advance the worm'against-the'applied drag of the brake.

These ratcheting mechanisms include a wheel having relatively large teeth and the pawl for "operating thereon is mounted'on an armwhichis oscillatedthroughout a greater or a lesser angular extent in accordance with the position of certain parts controlled through a whiproll or other mechanism which is in turn positioned in accordance-with the tension-in the-waipthreads themselves. in these devices the-actual operation generally amountsto a relatively great advancing movement interspersed between periods of-dwell 'for the beam and other parts since, due to the fact that the ratchet wheel teeth are relatively long, there may be one or. more idle movements of tlie pawl each 'oflonger extent,'but still less than the distance between the teeth,.be'fore it actually grips the next tooth thereby to move the beam throughout a definite-angular extent to let off warp. As aresult of this the control shiftsback and forth'between positions where it permits verylittleorno motion at 'all for the parts to that where a maximum and effective movement is imparted to the beam, whereupon the cyclethenstarts again so that the nextamovementzis-very small, or at least something "far less thangthe movementrequired for advancing the ratchet Wheel fora completetooth. Of course, the direct result inscfar'asthe weaving'functionis concerned istha't the tension must increase appreciably in order'to caus'e the le -oil of warp threads whereupon the more extended: letclr' movement then causesan undesired relaxing of the .tension bcYondwhat wouldtheoretically be considered better practice.

Again, the fact that the ratchet-wheel teeth and the pawl operabletherewith have been of appreciable. sizehas necessitated theuse of fairly heavy spring means to keep the pawl in engagement with the teeth so that considerable noise has been experienced, especially whenflperating at higher speeds. 1

According. to 1 the, invention which will hereinafter be described in greater detail, an advancing means has been devised which maybe. moved throughout very smallwangular extents, or for greater extents according to the requirement of'the particular fabric being wovenand, actually advance the gear train and eventually 'thewarp beam for acct-responding distance, the possibilities being far greater in each direction than in'the usual pawl and ratchet wheel mechanism employed to this time. "The movement imparted to the beam through the gearing is preferably, although not necessarily, applied to a shaft which is adapted to drive a worm, the shaft being subjected to aretardingor,brakingaction as will hereinafter be explained in-detail. =Movement imparted through cam mechanism the actual eliect of which is governed by-a whip roll or other means responsive to warp tensionv is imparted to. an oscillating member which may takethe form of an inverted drum, the interior surface of whiehis adapted to beengaged, by, certain driving means including one or more eccentric rollers which are spring ,pressed to bear. against the driving surface exceptras removed therefrom by positive 'c'ontrolmeans adapted to be manually operated. The eliectof the oscillating driving member is conveyedthrough the rollers to,a driven member fixed-to the shaft aforesaid, and preferably, this driven member may also comprise thebrake drum upon which the retarding means is effective.

The eccentrically disposedrollers are so mounted and so related to the susface against which they engage in the drivingmember thatfthey are spring pressed into operative or bind extremely tightly so that for movements in the advancing direction, theparts are forced together so firmly that they may not slip. Movements inthe return or reverse direction merely drag the roller or rollers along the driving surface therebyto reengage at a point preparatory to the next forward driving impulse.

f While one of the primary purposes of the instant mechanism is to eflfect smooth drive increments of movement which may be as small as are required, and to eliminate premature wear, noisy action and other more or less undesired features of certain devices heretofore employed, it is to be understood that when required, the

novel driving means may advance the drum as rapidly as desired since, of course, the control may be such that the oscillating movement of the driving member is of V appreciable extent. That is the case when fabric is being woven in which there are relatively few picks per inch so that the warp must be released at a rapid rate.

However, for any and all fabrics, the motion is one which'is virtually continuous in that the advancing of the '.warp beam at each movement of the lay or other control that the invention is not limited to this preferred embodi-- ment and that the following disclosure is to be considered illustrative only. In the figures of drawing: i .Fig. 1 is a side elevation of a part of a loom to which the invention has been applied. V

7 Fig. 2 is a vertical section taken through the center line of the let-off advancing means of-Fig. 1.

Fig. 3 is a'detail view, certain parts being shown in section, of a manually operable disconnecting means employed with the invention.

Fig. 4 is a side elevation of the parts shown in Fig. 3.

Fig. 5 is a plan view with certain parts being broken away to show the interior of the novel advancing means herein described.

Fig. 6 is a vertical section taken at line 6-6, Fig. 5.

Fig. 7 is a side elevation of part of the mechanism of Fig. 5. 7

Fig. 8 is a sectional view of certain parts greatly enlarged. showing the details of one of the eccentricaliy mounted driving rollers.

Fig. 9 is a section of a part of the mechanism showing the manner in which one of the driving rollers is disengaged from its cooperating driving surface.

Now referring to Figs. 1 and 2, the let-ofi means is applicable to typical looms having a loomside 10, a warp ,beam 11 mounted on the usualbearings indicated by numeral 12 attached to the back of the loom, said warp beam having ring gear teeth'which are shown at 13 and which are normally in mesh with teeth of a pinion 14 after the beam has been properly mounted. Pinion 14 is fixed at the inner end of a shaft 15 rotated by a gear train presently to be described. The shaft 15 is carried in bearings or bushings mounted in brackets 16 and 17, these being bolted to'opposite sides of the loomside and serving as a rigid mounting means for shaft and other parts.

The shaft 15 has keyed at its outer end a worm wheel a by. This worm meshes an incidental part of the mechanism shown and has no direct bearing on the invention.

The outer end of the shaft 15 including the worm wheel 18 and other parts are housed within a casing 21 which is actually an integral extension of the bracket 17 and which has a cover 22, this casing being adapted to sustain other parts as will hereinafter be described. A vertically disposed shaft or spindle 23 is mountedv'in bearings '24 and 25 in the casing and within the casing, mounts a worm 26 which is keyed or otherwise suitably fixed to the shaft to be rotated. therew'th the worm wheel 18 and thus when shaft 23 is rotated, the warp beam 11 is also advanced through the worm, worm wheel, pinion 14 and' ring gear 13. V V V ,7

The worm wheel 18 permits the shaft 15 to slide there- 7 in but the two must rotate synchronously since they are 18 along with a hand wheel 19 by means of which the pathway for the beam is cleared so it may be mounted or removed without interference. As a beam is to be removed or while mounting a beam in the loom, the

provided with a suitable key. Shaft 15 may be moved outwardly or inwardly as heretofore mentioned, but is always rotated by the worm and wheeldrive.

' The vertical shaft or spindle bearing 25 a flanged driven member which is also abrake drum, this member being indicated by numeral 27 and preferably being keyed, set screwed or otherwise suitably V V secured to the shaft.

As illustrated in Figs. 1, 2, 5 and 6, the drum'27 is retarded by means of brake shoes 28 and 29, the latter being provided with a laterally projecting notched lug 3%) which engages a pin 31 fixed in a boss 32 on the casing 21 so that the brake shoes are maintained against rotation. provided with a spring pressed releasing means at the opposite side, this releasing means comprising a hand operated cam lever 34 pivoted at 35 at one end of a bolt or stud 36 which projects through an apertured boss, 37

on one of the brake shoes and a similar boss 38 on the other. A spring 39 adjustably held in place by a nut or collar 40 maintains the parts in properly related adjustment so that as the lever 34 is moved to the clamping position, Fig. 5, the brake shoes are applied to the drum for retarding it in accordance with a force more or less governed by the tension in spring 39. That retarding force will be great enough to resist the tendency of the loom parts including the lay at beat-up to draw warp from the beam, but will not be efiective to resist the positive advancing movement of the warp beam rotating mechanism herein described. When the beam is to be rotated by a hand wheel 41'at the top of shaft 23, the

lever 34 is swung outwardly to release the brake shoes so that the effort required to rotate the beam manually may be maintained at a minimum.

able as to its length which is adapted to convey motion 7 from other mechanism presently to be described, to the driving member 42. For the purpose, of imparting periodic reciprocatory movements to the link44, a cam 45 fixed on the cam shaft 46 of the loom is engageable with a follower 47 positioned for rotation on an extension 48 projecting laterally and forwardly from the lowermost arm 49 of a two-armed lever pivoted at 50, the upper arm 51. of which is interconnected by a second link 52 to an arm 53 movable with the whip roll 54, this latter mechanism being ofany well known type such as may commonly be employed for thepurpose. The roll and arm 53 are moved in accordance with the'tension in the warp sheet so that as the tension in the warp increases, the parts are positioned to swing the arm 53 and eventually the two-armed lever forwardly of clockwise as viewed in Fig. 1, thereby moving the extension 48 and 21 and adjacent its lower end 23 also carries above the They are linked togetherat 33 and are the follower 47 to a-position where the eccentricity or throw of cam 45 may have a greater effect thereon. In the event the warp sheet-becomes more lightly tensioned, the whip roll moves'upwardly drawing arm 53 to the rear and positioning the follower 47 forwardly of the loom or in a position where thecam 45 becomes less efiective or, in fact, may have no effect at all.

Since the depending arm 49 is connected by the link 44 to the driving member, the effect ofthe cam 45 is conveyed thereby in accordance with the response of the mechanism to the tension in the-warp sheet as above described,'so that a greater or a lesser oscillatory movement is impafied to the driving member 42.

Now referring to Figs. and 6, the driving member 42 is actually comprised of an inverted drum 55 having a hub 5'61 which is freely rotatable on a bushing 57 on shaft or spindle 23, this drum being maintained in properly elevated position by the flanged bushing 58 which is interposed between it and the top of the brake drum and driven member which is actually keyed or otherwise fixed to the shaft 23. A plate 59 is bolted or otherwise secured to the top of drum 55 and it is to this plate that the link'44 is connected. If desired, the extending lug or arm to which the link is attached may be an integral part of drum 55 rather than an attached piece.

The brake drum or driven member 27 actually serves a dual function in that it receives the driving impulses from the drum 55 to rotate shaft 23, as well as forming a part of the brake.

The drive froni'the drum 55 through to the driven member 27 is efiected through one or more rollers 60 which, in efiect, have their peripheries eccentrically disposed to the pivots 61 about which they are'adapted to turn as governed by coil springs 62, Fig. 8, one end 63 of each spring being connected within an aperture in-the roller itself Whi e the other end is passed through a similar o ening or anchoring point'in the pivot for the roller. Each of these pivots is, in effect, an elongated pin inserted in an appropriate opening therefor in the drum 27 and is held in place in any convenient manner, for example, by the locking set screw 63' which is threaded through a part of the drum to enter a groove in the pivot pin itself.

While it is conceivable that the drive might be effected with a single roller only, that would not be particularly practical since a plurality of rollers reduces the driving force required at each individual element, and also balances the forces involved thereby contributing to a state of equilibrium wherein each equally spaced roller exerts substantially the sarne amount of driving force and therefore involves balanced radial and other forces on the various elements.

The drive for the parts proceeds in a clockwise-direction, Fig. 5, so that the eccentricity of the rollers is such that, as more clearly illustrated in Pig. 9, the clockwise movement of one of the rollers itself tends to move its periphery into engagement with the internal surface of drum 55. The distance between the center of pin 61 and the adjacent surface of the drum is such that the roller binds or tends to lock against the driving surface as the spring 62. swings the roller about its pivot into engagement with that surface especially as the drum tends to turn that roller still further. The amount of eccentricity, diameters of parts, etc., are such that the binding or locking efiect is considerable and in efiect, the drive from drum 55 to driven member 27 is virtually a positive one so long as the rollers are permitted to move under the influence of their springs.

Of course, the driving strokes or oscillations are confined to one direction and the reverse movement merely returns the drum which then slides past the rollers so that a new grip may be maintained. The springs may be relatively light in tension, it merely being necessary that they move the rollers outwardly against the driving surface at all times except when the parts are positively controlled to disengage the drive. Since the rollers are pressed all) 6 against the driving surface at all times, there is no lost motion on advancing strokes since the driving elements lock almost immediately upon change of direction of movement.

At times it is desired to employ the hand wheel 41 for rotating the beam ahead or backwardly and at that'time the brake drums are released as above described and it is also necessary to disengage the roll or rollers in the event the rotation of the beam is to be effected in a reversed direction. For that purpose a plate 64 is pivoted concentrically with the shaft 23 and is interposed above {the hubof brake drum 27, but beneath the rollers 60.

The plate isslotted as at 65 to admit a small amount of angular movement about the shaft without interference with the pin or pins 61. Each of the rollers carries a downwardly directed pin 66 which engages within an elongated slot 67 which is of sufficient width to admit free movement of the pin therein, and also disposed'at such an angle that as the plate is moved counterclockwise, Fig. 5, each roller is swung'against the tension of its spring 62 to a position equivalent to that illustrated in Fig. 9. At that time the slot67 acts as a cam against the pin 66 thereby moving the roller as stated. The slots 67 are of sufiicient width so that they do not have any undesired effect upon the contact of the rollers with the driving surface of drum 55 when they are permitted to return to their normal position, Fig. 3. If desired, they may be utilized for the purpose of assisting springs 62 to press the rollers against the driving surface. Return movement is controlled by a spring 63 which is connected to an extension 69 from the plate and to any suitable fixed member 70, Figs. 3 and 6. The member 7a must be carried by the drum 27 since the drum, pins 61, rollers and the plate 64 all function and move as a unit. The drum 55 is oscillated as controlled by cam 4:3 under the influence of the whip roll 54- and its movements are conveyed through the rollers and pins to the driven member or brake drum 27 which in turn rotates shaft 23, worm 2.6 and the ear train as described. When it is desired to disconnect the drive from drum 58 to the warp beam, some one of the projecting fin ers 71, herein shown as three in number, which extend radially from plate 64 is manually gripped or pushed in a direction to withdraw the rollers and thereby to free the driving engagement of the parts whereupon the effect of the hand wheel is conveyed through to the warp beam without interference, it, of course, being desirable to release the brake at that time.

From the above it may be seen that the means for advancing the gear train is compact, may function with uniform advancing movements at each beat of the lay, or at suchother timed intervals as may be prearranged, and that the gearing is conveniently closed so that the efiect of dirt, lint, etc., are minimized while it is possible to lubricate the parts as necessary without the lubrication becoming a nuisance due to the fact that the parts are exposed. The mechanism is relatively free from wear and since it operates smoothly and without relative movement of parts over others while under heavy spring tension as in the case of the usual pawl and ratchet mechanism, it is virtually silent.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive concept may be carried out in a number of ways. The invention is, therefore, not to be limited to the precise details described, but is intended to embrace all variations and modifications thereof falling within the spirit of the invention and the scope of the claims.

I claim:

1. In a loom having a warp beam from which a warp sheet is drawn and a whip roll over which said warp sheet is passed, a warp let-01f means comprising gearing for advancing said warp beam as governed by tension in said warp sheet and means for advancing said gearing which comprises a periodically oscillated driving drum having an internal driving surface, a driven member motion from the driving drum to the member during oscillations in-one direction which comprises a pivot on said driven member, an eccentric roller mounted on said pivot so that when turned about the pivot it may engage the driving surface of the drum, spring means normaliy urging the rollerinto contact with the said surface, and

means including a manually operable plate pivoted concentrically with said drum and member manually engageable projections extending from said plate, a cam slot in the plate and a pin carried by the roller and engaged within the slot for withdrawing the roller against the said spring means and from contact with said driving surface, and a spring means connected to said plate for normally retaining it in a position so that it has no etfect upon the roller.

2. In a loom having a warp beam from which a warp sheet is drawn and a whip roll over which said warp sheet is passed, a warp let-off means comprising gearing for advancing said warp beam as governed by tension in said warp sheet, said gearing including a worm and worm wheel and a shaft extending from said Worm on which is mounted means for advancing said gearing which comprises a periodically oscillated driving member, a member interconnected to said gearing which is comprised as and performs the dual function of a brake drum and a driven member by which impulses from the driving member are conveyed through to the said gearing, and means for interconnecting the driving and driven members to impart motion from the former to the latter which includes an eccentric roller rotatable on a pivot carried by one member and engageable with a cooperating driving surface on the other and spring means to press said roller into contact with said surface during oscillations of the driving member in one direction, but. permitting it to slip in the reverse direction, and manually operable means for rendering said roller ineffective to impart motion from either the driving or driven memher to the other which comprises a member pivoted on said shaft extending from said worm and interposed between the driving and driven members, means defining a slot in said manually operable means through which said roller pivot passes and a pin and slot connection between said manually operable means and the roller by which, as the said means is rotated about said worm' shaft, the roller is withdrawn from engagement with the driving member, a spring for normally maintaining the means in one position and an extending finger projecting beyond the driven member for moving the manually operable means against the tension of said spring.

3. In a loom having a warp beam from which a warp sheet is drawn and a whip roll over which said warp sheet is passed, a warp let-off means comprising gearing for advancing said warp beam as governed by tension in said warp sheet and means for advancing said gearing which comprises a shaft, an oscillating driving drum freely mounted on said shaft, a driven member fixed i to said shaft, an internal driving surface forming a part of said drum, a plurality of pivot means carried by said member and extending parallel to the shaft-and into said -drum, an eccentric roller on each pivot means having its least radius less than the distance from the pivot center to the driving surface and its greatest radius slightly more than that distance, and a spring for each roller fixed at one end toits roller and at the other end to the roller pivot and tensioned to urge the roller into contact with the said driving surface and means manually operable for simultaneously withdrawing said rollers from contact with said driving surface, said means comprising a disk pivoted on said shaft, slots in said disk through which said pivots pass to provide for oscillating the disk relatively to the driven member and pivots, a pin projecting from each roller and other cam slots in the disk, one for each pin, so disposed that as the disk isswung about the shaft the cam slots aifect the rollers through sheet is drawn and a whip roll over which said warp,

sheet is passed, a warp let-off means comprising gearing for advancing said warp beam as governed by tension in said warp sheet and means for advancing said gearing which comprises a periodically oscillated driving memher, a driven member interconnected to'said gearing and means for imparting motion in one direction from said driving to said driven member which comprises a pivot pin on one member, an eccentric roller carried by said pin, a roll engaging surface forming a part of the other member and resilient means for biasing said eccentric roller into engagement with said surface, the eccentricity of said roller being so disposed that, during movement of the driving member in one direction driving contact is established, but in the opposite. direction the roller may slip past the roll engaging surface, and manually operable means for rendering said roller inetfective to impart motion from either the driving or driven member to the other which comprises a member concentrically pivoted with said driving and driven members,

a spring normally maintaining it in one position and manually engageable means for moving it against the resistance of said spring and a pin and slot connection between the said member and roller by which, as the memberismanually moved, the rolleris withdrawn from" engagement with the cooperating roller engaging surface.

References Cited in the file of this patent UNITED STATES PATENTS 

